Balanced cut-off valve.



Patented Jan. 30, |900.

. M. HFWLT.

BLNCED CUT-OFF VALVE.

(Application filed May 16, 1899.)

(No Model.)

OLOF MAGNUS HOFWOLT, OF ROSTOCK, GERMANY.

BALANCED CUT-OFF VALVE.

SPECIFICATION forming part of Letters Patent No. 642,228, dated January 30, 1900.

application tiled May 16, 1899. Serial No. 716,976. (No model.)

To @ZZ whom, it may concern:

Be it known that I, OLoF MAGNUs HoF- WOLT, manufacturer, a subject of the Grand Duke of Mecklenburg, residing at Patriotischer I/Veg 106, Rostock, in the Grand Duchy of lllecklenburg and German Empire, have invented certain new and useful Improvements in Balanced Cut-Off Valves, of which the following is a full, clear, and exact description.

The device relates to cut-off valves and means for balancing the same. It consists in a slide-valve provided with a semicylindrical balance-plate and cut-off valve.

Figures l, 2, and 3 represent this relieving device in longitudinal section, cross-section, and elevation, while Fig. 4. illustrates the bottom slide with the expansion-slide half inserted, and Fig. 5 a development of the slidesurfaces.

This distributing-slide, which is similar to a Rider slide-valve, consists of the bottom slide a, having straight channels provided upon the bottom slide and spiral channels upon the rearsnrface, and of the expansionslide b, which, as a closed hollow slide, has below two spiral channels and upon the back one straight channel. Closely applied upon both slides is the relieving or discharging plate c, with hollow piston CZ, which latter is tightly packed and tightened against the entering' steam in a cylindrical portion of the cover of the slide-casing o by means of inserted washers e. The discharging-plate c is immovable in the direction in which the slides move, but can be adjusted at right angles thereto by means of the set-screws s,

The steam enters through the pipe j into the chamber h, arranged outside the cover of the slide-casing and closed up by means of a cover g. From the chamber the steam passes through the port z' into the piston d, then through the channel 7o into the dischargingplate c, and then to the channel l into the hollow expansion-slide b, from which latter it can pass through the two channels m into the bottom slide a and into the steam-cylinder.

It is evident from the preceding that as the hollow piston d is tightly closed by the washers e and as the bottom slide ct and the eX- pansion-slide b closely move between the slide-surface n and the discharging-plate c the steam never can arrive into the slide-casing o, pressing therein upon the slides. On the contrary, the steam will only press upon the hollow piston d, which by the proper adjustment of the set-screw s is prevented from transmitting the pressure upon the slides, thus relieving both slides from the steampressure.

What I claim, and desire to secure by Letters Patent, is-

In a device of the character described, a slide-valve provided with the semicylindrical seat, a piston cut-ott valve for the seat, and a semicylindrical balance-plate having reciprocatin g motion with the cut-od valve, and the balance-plate having a vertical motion toward the cut-off valve.

In witness whereof I subscribe my signature in presence of two witnesses.

OLOF MAGNUS HOFWOLT.

Witnesses:

E. H. L. MUMMENHOFF, OTTO W. HELLENRICH. 

